To build a suppressor, start by cutting a 2-inch PVC pipe to a length of 10 inches. Cut a 1-inch PVC pipe to a length of 12 inches. Use a marker and a tape measure to mark out a straight line of evenly spaced dots on the 1-inch pipe. Rotate the pipe by 90 degrees, and do the same again.
Drill through each hole until the drill bit goes through the opposite side of the pipe. Use a sandpaper or a rotary tool to smooth the inside and outside surface of the 1-inch pipe. Do the same with the inside surface of the 2-inch pipe.
Place the 2-inch pipe on a rubber or wooden surface, and trace the circular shape created by the pipe. Place the 1-inch pipe at the center of the circle, and trace its circle too. Cut out the shapes so that you're left with a circullar disk with a hole at the center. Repeat this step so that you have two disks.
Next, slide the 1-inch pipe inside the 2-inch pipe such that the two pipes are aligned on one side. Glue the disk you created in the space between the two pipes. Stuff the space between the two pipes with mattress foam, and glue the second disk to the other end of the pipes.